We report the controlled integration, via Dip Pen Nanolithography, of monolayer dots of ferritin-based CoO nanoparticles (12 Bohr magnetons) into the most sensitive areas of a microSQUID sensor. The nearly optimum flux coupling between these nanomagnets and the microSQUID improves the achievable sensitivity by a factor 100, enabling us to measure the linear susceptibility of the molecular array down to very low temperatures (13 mK). This method opens the possibility of applying ac susceptibility experiments to characterize two-dimensional arrays of single molecule magnets within a wide range of temperatures and frequencies.
@article{arxiv.1103.3975,
title = {Ac magnetic susceptibility of a molecular magnet submonolayer directly patterned onto a microSQUID sensor},
author = {M. J. Martínez-Pérez and E. Bellido and R. de Miguel and J. Sesé and A. Lostao and C. Gómez-Moreno and D. Drung and T. Schurig and D. Ruiz-Molina and F. Luis},
journal= {arXiv preprint arXiv:1103.3975},
year = {2015}
}